Marble Run Wall

1. 1

   Pick your wall

   A fridge side, closet door, or big cardboard box also works. Ask before you tape.

2. 2

   Place the finish line

   Tape a cup at the bottom. Everything above must funnel into it.

3. 3

   Cut tubes in half lengthwise

   You want open troughs, not tunnels. Have a grown-up help with the scissors.

4. 4

   Tape the first ramp at the top

   Slight downward angle. Test with a marble. If it stops, steepen the angle.

5. 5

   Add three more ramps

   Each ramp catches the marble from the last one. Alternate directions so the marble zigzags down.

6. 6

   Add one tunnel

   Leave one tube whole. Marble goes in one end, comes out the other. Feels like magic.

7. 7

   Time it

   Count the seconds from drop to cup. Try to slow it down to 10 seconds by adding more ramps.

safety · Marbles are choke hazards — keep them away from little siblings and pets.